Apparatus for casting metal billets and the like



May 17, 1955 L. M. EcKEs APPARATUS FOR CASTING METAL BILLETS AND THELIKE Filed June 27, 1952 2 Sheets-Sheet l lull-W11 INVENTOR.

BY V

E El?! A TTO/FA/E Y May 17, 1955 L. M. BECKES 2,708,298

APPARATUS FOR CASTING METAL BILLETS AND THE LIKE Filed June 27, 1952 2Sheets-Sheet 2 INVENTOR.

BY MBAMQLQM A TTORNE Y United States Patent APPARATUS FOR CASTING METALBILLETS AND THE LIKE Lloyd M. Beckes, Union, N. 1., assignor to Americansmelting and Refining Company, New York, N. Y., a corporation of NewJersey Application June 27, 1952, Serial No. 296,035

3 Claims. (Cl. 22-78) This invention relates to the making of castingsand more particularly to castings of shapes suitable for furtherprocessing, as for example, billets or slugs of tin-lead solder forextrusion into wire.

According to prior practice, billets, such as those in question, areusually cast by hand-pouring the molten solder into vertical,cylindrical, water jacketed molds having a lower end closure. Thebillets are discharged from the molds after cooling and solidificationof the solder, by inverting the mold, if trunnion mounted; or byreleasing the bottom closure plate if the molds are mounted in a fixedposition.

Billets cast by this prior practice have several objectionablecharacteristics, among them being dross or oxide inclusions, airinclusions, cold shuts, and starved areas, all of which constituteimperfections in the extruded product, which result in difiiculties insubsequent processing.

Objects of the invention are to overcome the objection of priorpractices and, at the same time, reduce cost, im-

prove reliability of manufacture and produce a better finished product.

Other objects of the invention are to produce billets possessingimproved physical and metallurgical properties, particularly those ofuniformity of dimension, freedom from dross or oxide inclusions andstarved areas,

and so far as possible, reduced segregation of constituent metals.

Other objects will be apparent from the following description and claimswhen considered with the accompanying drawings in which:

Fig. 1 is a schematic central vertical section through j.

Fig. 2 is a larger scaled central vertical section of the invention,showing the mold in the discharge position; Fig. 3 is a fragmentary plansection taken on line 3-3 of Fig. 2;

Fig. 4 is a fragmentary vertical section taken on line hole 27 throughwhich the solidified billet drops.

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circulates molten metal through the header 12, flow being indicated bythe arrow. Hand operated valve controls the pressure of the molten metaldelivered to the mold 17 while servo-motor-operated control valve 16 isopen. Closure of valve 16 raises the metal pressure in header ormanifold 12 for the purpose of filling the mold 17.

This arrangement is, in general, similar to that disclosed in Palmer andBeckes Patent No. 2,459,892, dated January 25, 1949. Although a singlemold 17 is shown, it will be understood that any suitable number ofmolds 17 may be distributed along the length of manifold 12 so that thesame metal circulating system may feed the several molds.

The molding machine will first be only generally described. It comprisesa stationary frame supporting a fixed mold plate 2%? having a fill port26 to which the header 12 is connected. Plate 20 also has a dischargeSlid ably mounted on mold plate 20 is slide plate 21, the latter havingsecured thereto a vertically disposed mold cylinder 22. The stationaryframe supports a mold cover 23 normally held spaced from the top of themold cylinder 22 by springs 49.

A servo-motor cylinder 24 is mounted on the stationary frame for thepurpose of pushing the mold cover 23 down against the mold cylinder 22before the latter is filled with molten metal. A double actingservo-motor cylinder 25 is connected to slide plate 21 for moving moldcylinder 22 from filling position over port 26, as shown in full linesin Fig. 1, to discharge position centered over hole 27, as indicated bythe dot-and-dash lines in Fig. 1. The construction and operation will bedescribed more fully below.

Referring now also to Figs. 2 and 3 for a more complete description, thecasting machine comprises a stationary frame made up of suitablestructure members, indicated in general by 30. The frame supportsstationary mold plate 20. Slide plate 21 slides in guides or ways 31secured to mold plate 20. Double acting hydraulic cylinder 25 is securedto the stationary frame and has a piston rod 32 secured to slide plate21. A stop member 33 secured to the frame limits movement of slide plate21 in one direction in which position the mold cylinder 22 is exactlycentered over the discharge hole 27. A suitable stop limits the movementof the slide plate in the other direction to approximately center themold cylinder 22 f 7 over the feed port 26.

44 of Fig. 2, illustrating the sealing ring at the feed port of thepressure header, through which the molten In the following description,specific terms will be used i for purposes of explaining the embodimentused toillustrate the invention, but these and broader terms are used inthe claims which are intended to define the invention in as broad ascope as the prior art will permit.

Referring now to the drawings, and more particularly to the schematicdiagram of Fig. 1, the kettle 10- contains a bath of molten metal (forexample, tin-lead solder) which is to be cast by the casting machine.

The metal is kept in molten condition at suitable temperature by fuelburner 14. Pump 11 driven by motor 13 continuously part of a coolingjacket.

It will be noted that slide plate 21 has a part providing a cover forfeed port 26 in the billet discharge position illustrated in Fig. 2. Thebillet in this figure, indicated by 44, is shown being discharged bydropping from the mold by gravity.

Mold cylinder 22 comprises an inner cylinder 35 secured to baseplate 21.Wall 35 supports upper ring 36. Outer cylinder 37 surrounds innercylinder 35 forming Outer cylinder 37 is connected to a lower ring 38and to an upper ring 39. Lower ring 38 is suitably connected to slideplate 21; upper ring 39 is suitably connected to ring 36.

It willbe noted that outer wall 37 extends into annular recesses 40 and41 respectively. Pipes 42 and 43 are connected to rings 38 and 3Q whichin elfect form annular ducts. It will be understood that pipes 42 and 43are connected through flexible conduits to suitable stationary supplyand discharge water pipes (not shown), permitting the mold cylinder tomove back and forth between fill and discharge positions.

It will be understood that the various parts of the mold cylinder 22 maybe connected together in any suitable manner. As indicated, welding isrelied upon in most instances. The water jacket permits only a thinlayer of water throughout substantially the entire cooling area of themold cover 23.

amazes 3 that part of the mold in contact with the hot molten metal.This permits high efliciency cooling using high velocity water how withreduction of skin effect.

Cold water is fed in through upper pipe 43 into the upper part of thejacket and withdrawn from lower pipe' 42 out of the lower part of thejacket; this makes the upper part of the mold coolest to obtaindirectional cooling of the casting from the top down so that the lowerpart of the billet will freeze last.

Mold cover 23 comprises a lower plate 46 and upper plate 47', the platesare so shaped as to form a thin water jacket space therebetween. Acentral boss 53 is secured to upper plate 47 to transmit the pressureexerted by air cylinder 24 to lower plate 46. Pipes 50 and 51 providefor circulation of cooling water. These pipes are connected throughflexible connections to suitable stationary pipes to permit constantcirculation through the water jacket, and yet allow the mold cover 23its limited upand-down movement, as described below.

The mold cover 23 is supported by studs 48 screwed 2 into the top of thecover and slidably engaging the adjoining frame members Sd. Helicalsprings 49 are interposed between the heads of the studs 48 and theframe members to yielda'oly hold the mold cover 23 in uppermostposition, away from the mold cylinder 22, as indicated in Fig. 2. Aircylinder 24 is secured to the adjacent frame member 39 and has a pistonrod 52 connected to Application of air to the cylinder 24 forces thecover down against the mold when the latter is infilling position. Whenair is released from the cylinder 24, the springs 49 raise the cover 23ofi the mold cylinder 22.

For the purpose of permitting air to escape from the mold during fillingwith molten metal, the top of the mold cylinder may have one or moregrooves, indicated by 55 -in Fig. 2. A brush 56 may be secured to theadjacent frame member 30, which brush sweeps out the grooves, as

the mold cylinder moves back and forth between fill and dischargepositions. This insures always having open grooves by removing any finof cast metal which may end 61 engaging seat 59. The inner surface ofthe sealing ring 69 is conical and extends between a relatively largefeed opening in the wall of header 12 to the'relatively small feed port26. a

It will be noted that the engagement between ring 60 and mold plate 2%is of limited area; also that clearance space is provided between thering 60 and bend 57, on

the one hand, and the underside of mold plate 20, on the other hand, asindicated particularly in Figs. 4 and 5.

The sealing ring 6!) is preferably of soft iron and has machined andlapped surfaces engaging similarly treated surfaces on header 12 andmold plate 2i). The material of the ring 69, as well as other parts ofthe apparatus contacting the molten metal, is of such nature as to avoidany chemical action by the molten metal on the machine.

The sealing ring 60 is clamped in position by a clamping arrangementcomprising a bar 65 and a pair of studs 66 screwed up into the moldplate 20. The bar 65 is slidably mounted on the reduced ends of thestuds 66 and is 'urged upwardly by springs 67 disposed under the bar'65.and acting against nuts on the ends of the studs.- A set screw 68threaded into the bar 65 presses the header 12 upwardly.

The meeting spherical surfaces on the sealing ring 60 and header 12permit any slight adjustment of the header as it is clamped up intoposition, while insuring a liquidtight engagement between the ring andits connected parts,

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. 4 V regardless of exact position of the header. The return pipe of themolten metal circulating pipe is supported by the frarne 30 at 63 inFig. 2.

Operation The various movements of the parts may be controlled by aworkman initiating each movement by admitting fluid to the severalcylinders at the proper times Or, the.

control cylinder may be operated by a suitable electrical system oftimers, relays, switches, solenoid operated valves, etc. (not shown). 7

A description of the operations and movements in a complete cyclefollows:

Assume that the flow of molten metal has been established in the header12 and circulating piping, and that the rate of flow has been adjustedby the hand control valve 15 so that molten metal within the inlet port26 stands at a level just below the top surface of the mold plate 259.The electrical and pneumatic-hydraulic circuits are so arranged that,when the electrical control system is tie-energized, the mold 22 is inthe discharge position and the inlet port 26 is blanked off by thebottom part or the slide plate 23 (see Fig. 2

When the electrical control system is energized, the hydraulic cylinder25 is operated to cause the mold 22 to move from its discharge to itsfill position, uncovering the inlet port 26. The fill position is shownby the position of the mold cylinder 22 in full lines in Fig. 1.

When the mold cylinder 22 reaches its 111 position, a switch (not shown)is actuated, causing the mold cover 23 to move downward against the topof the mold."

When the mold cover 23 has completed its downward movement, anotherswitch (not shown) is actuated, causing the pressure control valve 16 tostart to close. As the pressure control valve 3.6 closes, molten 'metalpressure within the header. 12 increases, causing metal to flowinto andfill the mold. The extreme pressure in the header is maintained duringthe time required for solidification of the metal in the ,mold so as tofeed the casting with hot metal.

When the necessarytime for solidification of the metal in the mold haselapsed, a timer (not shown) in the electrical control system acts tocause the pressure control valve 16 to open, lowering the pressure inthe header 12 to its preset low value and, at the same time, causing themold cover 23 to rise from the top of the mold. When the mold cover 23reaches itsextreme release position, a switch (not shown) is actuated,causing hydraulic cylinder 25 to move the mold cylinder 22 on mold plateEll-from its fill position toward its discharge position.

When the mold cylinder 22 reaches its discharge position, which is inregister with clearance hole 27 in the mold plateZt), the billet 4-4falls by gravity from the mold sealing ring.

Comments 7 It will be noted that the area of contact between the 'r'noldplate 2% and the sealing ring 69 is relatively small, and so tends toreduce the amount of heat transmitted from the sealing ring to the moldplate. It will also be noted that the area of contact between thesealing ring 69 and the header 12 is relatively large and so tends tofavor the transmission of heat from the header to the Also, the top ofthe sealing ring 61 is closeto the top of the mold plate 2%. The netresult of such an arrangement is, in effect, to bring the areas withinthe header, where the metal is always molten, into the closest possibleproximity to areas within the mold cavity where it is desired to cooland solidify metal admitted through the inlet port.

In other words, the'i. yention brings the areas of molten and solidifiedmetal as close together as possible physically and, at the same time,has these areas as far apart as possible thermally.

Through the use of a sealing ring, proportioned as outlined above, thefollowing favorable conditions for the production of a sound casting areobtained, so far as the relationship between the header and the mold areconcerned: a minimum loss of heat from the molten metal circulatingthrough the header and flowing to the mold, making it possible tomaintain more nearly uniform temperatures at the inlet ports whenmultiple molds are used; the ability to keep the lower portions of themold at a lower temperature, thus promoting more rapid cooling of thecasting; the ability to establish a quite sharp line of demarcationthermally, at or near the molten metal entry port, so that molten metal,which has entered the mold, may be quickly cooled and solidified; theability to maintain the metal within the entry port and sealing ring ina molten state and, by so doing, make available a path of supply formolten metal under pressure to feed to the casting to compensate for thedecrease in volume due to cooling and solidification.

The invention also provides the following advantages especiallyimportant in the casting of billets: (1) bottom filling of the mold; (2)maintenance of the maximum molten metal pressure at the mold inlet portduring the time required for cooling and solidification of the castingso as to feed hot metal to the casting to compensate for the shrinkageof solidification, and (3) rapid cooling applied in such a manner as toprovide for directionally controlled progressive solidification of thecasting from top to bottom of the mold.

The use of this invention provides considerably more leeway inmaintaining correct timing of the several events, correct temperaturesof mold and circulating metal for any particular mold shape or size, andparticular composition of cast product.

While the invention is particularly adapted to the casting of whitemetals and lead alloys, it will be understood that the principlesthereof are applicable generally to the casting of other metals andalloys which present problems similar to those encountered in castingwhite metal. Further it will be appreciated that various omissions,substitutions and changes may be made by those skilled in the artwithout departing from the spirit of the invention.

What is claimed is:

1. In a molding apparatus for casting molten metal and the like having astationary frame, a mold plate secured to the frame, a mold chargingposition on said plate, a mold discharge position on said plate spacedfrom said charging position, a mold having an opening in one end thereofslidably mounted on said end on said plate and being capable of beingslid on said plate from the charging position to the dischargingposition, a molten metal inlet port passing through the plate at thecharging position thereon and in communication with said mold openingwhen the mold is in charging position on the plate, and a conduit forsupplying molten metal to said inlet port, the improvement comprising arecess in said mold plate encompassing said port on the side of saidplate which is opposite to that facing the mold, a seat on said moldplate in said recess concentric with said port and in close proximity tothe surface of said plate facing the mold, a portion of said conduitbeing disposed in said recess, a molten metal outlet in said portion ofsaid conduit generally aligned with said port, a seat on said conduitencompassing said outlet, a sealing ring disposed in said seats, thecontact surface between said ring and said conduit seat being largerthan the surface contact between said ring and said mold plate seat,said ring being otherwise spaced from said mold plate and said conduitalso being spaced from said plate, thereby to promote heat fiow intosaid sealing ring and to reduce heat flow from said ring to said moldplate.

2. In a molding apparatus for casting molten metal and the like having astationary frame, a mold plate secured to the frame, a mold chargingposition on said plate, a mold discharge position on said plate spacedfrom said charging position, a mold having an opening in one end thereofslidably mounted on said end on said plate and being capable of beingslid on said plate from the charging position to the dischargingposition, a molten metal inlet port passing through the plate at thecharging position thereon and in communication with said mold openingwhen the mold is in charging position on the plate, and a conduit forsupplying molten metal to said inlet port, the improvement comprising arecess in said mold plate encompassing said port on the side of saidplate which is opposite to that facing the mold, a seat on said moldplate in said recess concentric with said port and in close proximity tothe surface of said plate facing the mold, a portion of said conduitbeing disposed in said recess, said portion of the conduit comprising areturn bend having a molten metal outlet therein in general alignmentwith said port, a seat on said conduit encompassing said outlet, asealing ring disposed in said seats, the contact surface between saidring and said conduit seat being larger than the surface contact betweensaid ring and said mold plate seat, said ring being otherwise spacedfrom said mold plate and said conduit also being spaced from said moldplate, thereby to promote heat flow into said sealing ring and to reduceheat flow from said ring to said mold plate.

3. Apparatus according to claim 2 in which said mold plate ishorizontally disposed, said mold is slidably mounted on the uppersurface of the mold plate, and said recess comprises an annular recessand larger recess encompassing the annular recess, said annular recessproviding the said seat on the mold plate for said ring and the largerrecess providing space for the portion of the circulating conduitdisposed therein.

References Cited in the file of this patent UNITED STATES PATENTS180,124 Guels July 25, 1876 471,527 Madden Mar. 22, 1892 543,700 PotterJuly 30, 1895 934,940 Shantz Sept. 21, 1909 1,318,558 Held Oct. 14, 19191,912,981 Hoy June 6, 1933 1,913,945 Morris et a1 June 13, 19331,950,568 Richards Mar. 13, 1934 1,952,201 Flammang et a1 Mar. 27, 19342,459,892 Palmer et al. J an. 25, 1949 2,526,753 Huck Oct. 24, 1950

1. IN A MOLDING APPARATUS FOR CASTING MOLTEN METAL AND THE LIKE HAVING ASTATIONARY FRAME, A MOLD PLATE SECURED TO THE FRAME, A MOLD CHARGINGPOSITION ON SAID PLATE, A MOLD DISCHARGE POSITION ON SAID PLATE SPACEDFROM SAID CHARGING POSITION, A MOLD HAVING AN OPENING IN ONE END THEREOFSLIDABLY MOUNTED ON SAID END OF SAID PLATE AND BEING CAPABLE OF BEINGSLID ON SAID PLATE FROM THE CHARGING POSITION TO THE DISCHARGINGPOSITION, A MOLTEN METAL INLET PORT PASSING THROUGH THE PLATE AT THECHARGING POSITION THEREON AND IN COMMUNICATION WITH SAID MOLD OPENINGWHEN THE MOLD IS IN CHARGING POSITION ON THE PLATE, AND A CONDUIT FORSUPPLYING MOLTEN METAL TO SAID INLET PORT, THE IMPROVEMENT COMPRISING ARECESS IN SAID MOLD PLATE ENCOMPASSING SAID PORT ON THE SIDE OF SAIDPLATE WHICH IS OPPOSITE TO THAT FACING THE MOLD, A SEAT ON SAID